pediment (n.)

in architecture, "the triangular part of the facade of a Greek-style building," 1660s, alteration of periment, peremint (1590s), a word of unknown origin, "said to be a workmen's term" [OED]; probably a dialectal garbling of pyramid, the connection perhaps being the triangular shape. Sometimes associated with ped- "foot." Other possibilities include Latin pedamentum "vine-stalk, prop," and Italian pedamento, which at the time this word entered English meant "foundation, basework, footing." Meaning "base, foundation" is from 1726, by influence of Latin pedem "foot."